Variable-pressure hydraulic elevator



2 QM N An M R E E H W T VAEIABEE PRESSURE EYDEAULIG ELEVATOE. No. 398,044. 1889.

Patented Feb 19 MAN JWN.

(No Model.) 2 Sheetys--Slieet4 2.

T. W. HEERM-ANS.

VARIABLE PRESSURE HYDRAULIC ELEVATOR.

No. 98,044. y Patented Feb. 19, 1889.

IINEEED STATES PATENT @Erica THADDEUS \V. HEERMANS, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE CRANE ELEVATOR COMPANY, OF ILLINOIS.

VARIABLE-PRESSURE HYDRAULJC LEVATOF?.

SPECIFICATION forming part of Letters Fatent No. 398,044, dated February 19, 1889.

Application filed July 12, 1888. Serial No. 279,740. (No model.)

To aZZ whom i6 may concern:

. Be it known that I, THADDEUS IV. HEER- MANs, of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Variable-Pressy head or pressure, so that the power consumed is the same whether the load raised is amaXimum or a minimum, the power being always i r a maximum.

ing the quantity of water to suit the changes in the load or by varying the pressure under which it is supplied.

tion relates to apparatus and devices for automatically proportioning the pressure to the l l t Thelatteris the method 1 which I have chosen to adopt, and myinventhey are not here illustrated.

load with accuracy a-nd without the intervention of the operator, who has only to inanipulate the ordinary handling-gear in the ordi- My invention consists in the parts and combinations hereinafter described, and pointed out in the claims.

a side elevation of an elevator apparatus en1- bodying my invention. Fig. 0

is a view,l

In the accompanying drawings, Figure l is partly in section, ofthe end of the water-cyl- 1 inder and its attached load-weighing eylini Whose hoisting cable or cables 3 pass in the the rod of piston 27.

usual manner over a pulley or pulleys, et, at the top of the shaft, and thence downward to the hydraulic engine 5. Herethey pass several times back and forth over the pulleys 6 and 7, and their ends are fastened to the anchor-piece 8, as more clearly seen in Figs. 2 and 9. Bolts 9 9 join the piece 8 to a plun- 5o ger, 10, working in a cylinder, ll, the latter being secured by bolts l2 to the main eylinder 5 of the engine, said main cylinder forming 'the fixed anchorage against which the strain of the cables is exerted. Leading from cylinder ll is a pipe, 13, to one side of the piston lll in cylinderld. From the otherside of piston le is a pipe,l5, to the pressure-tank 16. (Vide Fig. l.)

17 is a steam-pump, which takes water from the exhaust-tank 2O through pipe 2l and 6o forces it 'into tank lf3 through pipe 18. The use of a tank 1G is purely optional, as it is not needed for storage, the pumping being 'practically direct; but it is convenient for connecting the various lines of pipe, and is used as an air-chamber. Power may be economized either'by vary- 1 is a hydraulic valve of any approved pattern, which is operated by the elevator-attendant in any well-known manner. As the appliances for this purpose are well known 7c and form no part ol' the present invention rlhe pipes 2:3 and 2f-l connect said valve 22 to the pressure and exhaust tanks 16 and 20, respectively. Steam is admitted to the pump 17 through 7 5 the valve 19, which is shown in detail in Fig. As Awill be seen, it is a balanced valve, the steam-pressure on one disk, 25, being' counteracted by the pressure on the other disk7 2G. No novcltyis claimed for the valve 8o itself, and any other balanced valve might be used in its stead. v y

The disks and 2G are connected to the piston ll, and to a second piston, 27. One side of piston 27 is exposed to the pressure of 85 water from the pipe l-that is to say, the saine pressure as that on one 'side of piston la and in the prcssure-tank le. To this water-pressure on piston 27 is opposed 'the force of the spring 2S, which may be compressed eo more or less by the operation of the threaded hand-wheels 29 and 30, which, by means of the yoke 3l, connect' the spindle of valve 19 to The operation is as fellows: It is evident. that the load on the liftingcables will be accurately measured by the pressure on the wa= ter in cylinder 11, (ride Figs. 2 and 3,) and that such pressure will be communicated to the corresponding side of piston la. It is also roo evident that the pressure on the opposite side of piston 14; will correspond to that in the main cylinder, communication being' i'ree through pipes and 23. The valve 19 will thus be under the in tiuence of two opposing forces acting on piston li, and being connected, as described, to the piston 27, will also be under the influence ot' the opposing forces exerted by the spring 2S and the iiuidpressure from the main cylinder acting on said piston. The net result of these forces isthat the pressure from the main cylinder tends to close the valve 19, while t-he tension of the lifting-cables and the spring 28 tend to open it, and in order to have the apparatus work properly a certain balance or proportion must exist between these opposing' forces, as will appear. Suppose, now, that the operator puts the main cylinder in communication with the pump in order to make the car aswill also be insufficient to keep the valve 19 closed, and the combined tension ot' the cables and spring will open and keep open the valve 19; but if the pressure in the main cylinder exceeds the desired limit for which the apparatus is adjusted the valve 1,9 will close more or less and diminish or out olii the supply of steam to the pump. Of course in descending', as the water is simply let out oi' the cylinder' and no power is used, the func tions of my improved apparatus are not brought; into play.

'lhe function ot' springI 2S is plain from the iforcgoing description. 1f it were practicable to perfectly proportion the parts so that the proper relations would exist between the opposing forces acting on valve 19, then the spring 2S could be dispensed with; but as it is diilicult to secure such exact proportions between the various parts the introduction of a variable pressure-such as that acting on valve li-servcs to compensate for errors of proliortioning or variations in ease oi working. l therefore regard said spring or its equivalent as an important though not indispensable ieature of the apparatus.

Steam is saved by this device, because the pump is never working against a greater pressure than is necessary, the pump being held at a constant speed by any well-known governor to raise the load, while in the usual arrangement the head must be suiiieient to raise the greatest load the elevatoris designed to carry.

It is to be understood that a system of le vers--as, for example, shown in Fig. 5-01 any other equivalent ii'or the plunger 10, cylinder 1l, and pipe 13,if used to transmit pressure from the cables 3 to piston lll-,would be within the scope of my invention.

It is also obvious that the use of fluid-pressure above piston 27 is not absolutely necessary, because the comparative pressure on the opposite sides of piston 14 might be so pro portioned as to eounterbalance the spring 28. For example, the enlargement of plunger 10 would diminish the pressure per square inch below piston 14 and would render the pressure above piston 27 unnecessary.

l am aware that hoisting apparatus has been heretofore contrived in which the load on the car or the tension thereby imparted to the lifting-cables was utilized to open a valve, which admitted compressed air into the Water-tank, and thereby forced the Water into the main cylinder and lifted the car, such an apparatus being shown in Patent No. 220,47 9 to Johnson and Bailey; but as no means were provided for returning the water to the tank or cylinder if it should be permitted to escape the apparatus just described differs from my invention in that the management of the ascent and descent of the car requires the ma ni pulation by the atten dant of separate valves by which the air and water are independently controlled.

I am also aware that it is not new, broadly, to so connect the steam-valve of a pump that increase in the resistance will cause a greater supply of steanrto be admitted to the pump, and I do not claim such as myinvention.

I claim- 1. In a hydraulic hoisting apparatus, the combination of a tank or reservoir for containing the water supply, a steam -pump pumping therefrom direct to the main cylinder, a valve controlling said pump, a piston exposed on one side to thepressure from the main cylinder, and on the other to pressure produced by tension of the lifting-cables, said piston being so connected to said valve that the pressure from the main cylinder tends to close and the pressure produced by the li ftingcables tends to open said valve, and a valve controlled by the operator and adapted to admit water to the main cylinder from the pump or to permit the water to escape from the main cylinder to said tank, substantially as described.

2. The combination, with a control-valve, as 19, operated by a piston, 14, exposed on one side to pressure from the main cylinder and on the otherside to pressure produced by the tension ot the lifting-cables, of a regulatingspring, 2S, and a piston, 27, the pressure of said spring being opposed by Huid-pressure from the main cylinder, as and for the purpose set forth.

-THADDEUS YV. HEERLWIANS.

Witnesses:

J. I. VEEDER, P. H. T. MASON.

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